If you haven’t heard of The Toilet Paper Roll Test, it involves using a standard 10-11cm (4-4.3″) long and a width (diameter) of 3.5-4cm (1.38-1.57″), which is a 10.99-11.4cm (4.3-4.5″) girth (circumference). Now obviously there is variation to this size depending on brands, and countries so this isn’t an exact science.

The urban myth here is, if you can fit your erect penis inside a toilet paper roll easily and none pokes out the top, then you have a small penis. Likewise if some does poke out the top, but you can fit it over your penis easily you have a pencil dick or a small girth.